hCG Administration for Ovarian Induction
Administer 5,000 to 10,000 IU of hCG intramuscularly when at least three follicles reach ≥17 mm diameter with appropriately rising serum estradiol levels, followed by oocyte retrieval 36-38 hours later. 1, 2
Dosing Protocol
Standard Dose
- The recommended dose is 5,000 to 10,000 IU administered as a single intramuscular injection 3
- For ovulation induction in anovulatory women pretreated with menotropins, the FDA-approved dosing is 5,000 to 10,000 IU given one day following the last dose of menotropins 3
- A dose of 10,000 IU is specifically recommended in menotropin product labeling 3
Minimum Effective Dose
- Do not use doses below 5,000 IU - studies demonstrate significantly lower oocyte recovery rates (77.3%) with 2,000 IU compared to 5,000 IU (95.5%) or 10,000 IU (98.1%) 4
- There is no significant difference in oocyte recovery between 5,000 IU and 10,000 IU doses 4
- Subcutaneous administration of 250 μg recombinant hCG is equivalent to 5,000 IU urinary hCG and shows comparable ovulation rates (95.3% vs 88.0%) 5
Timing Criteria
Follicular Development Thresholds
- Trigger ovulation when at least three follicles measure >17 mm in diameter 1
- Serum estradiol levels must be appropriately rising at the time of hCG administration 1
- Monitor ovarian response with serial transvaginal ultrasound and serum estradiol measurements 1
Critical Timing Window
- Administer hCG exactly 24 hours after the last gonadotropin injection - delaying administration to 48-72 hours significantly decreases fertilization rates (57% vs 84%) and increases oocyte degeneration (9% vs 1%) 6
- Oocyte retrieval must occur precisely 36-38 hours after hCG administration 2, 7
Route of Administration
Intramuscular (Standard)
- Intramuscular injection is the FDA-approved and most widely used route 3
- Reconstitute powder with bacteriostatic water for injection per manufacturer instructions 3
- For 10,000 IU vial: use 1 mL diluent for 10,000 IU/mL concentration or 10 mL for 1,000 IU/mL for multiple dosing 3
Subcutaneous (Alternative)
- Subcutaneous administration is feasible and achieves similar pharmacokinetic profiles to intramuscular injection 8
- Subcutaneous route offers better local tolerability with fewer injection site reactions (pain and inflammation) compared to intramuscular urinary hCG 5
- Highest serum β-hCG concentrations are achieved with 10,000 IU administered subcutaneously 8
Special Populations and Modifications
High OHSS Risk Patients
- In women with estrogenic ovulatory dysfunction and hyperinsulinemia at high risk for ovarian hyperstimulation syndrome, consider switching to low-dose hCG (200 IU daily for 2-3 days) after FSH priming, followed by 5,000 IU trigger dose 9
- This modified protocol supports growth of larger follicles while reducing recruitment of smaller preovulatory follicles, thereby decreasing OHSS risk 9
- For patients with antiphospholipid antibodies, withhold anticoagulation 24-36 hours before oocyte retrieval and resume afterward 7
Poor Responders
- Patients stimulated with pure FSH (versus hMG) have lower successful oocyte recovery rates when suboptimal hCG doses are used (60% vs 84.1% with 2,000 IU) 4
- Ensure minimum 5,000 IU dose in all patients, particularly those receiving pure FSH protocols 4
Common Pitfalls to Avoid
- Never delay hCG administration beyond 24 hours after the last gonadotropin dose - this causes follicular atresia and poor fertilization despite normal steroid patterns 6
- Never use hCG doses below 5,000 IU - inadequate dosing results in failed oocyte retrieval in nearly 25% of patients 4
- Do not administer hCG before adequate follicular maturation (minimum three follicles ≥17 mm) as this compromises oocyte quality 1
- Inspect all parenteral solutions for particulate matter and discoloration before administration 3